Various structures are often subject to corrosion in a wide variety of environments and industries. Detection of that corrosion is often necessary or desirable for safety, maintenance, or other purposes. For example, pipes conducting corrosive acidic fluids at different levels often need corrosive sensing over an array of local areas of the pipe's interior. One conventional approach uses direct current (DC) magnetic sensing of surface corrosion with a magnetometer, where the DC magnetic sensing does not vary magnetic flux through material to be sensed with time.